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From 60092075ded3e51036fd018ba6d9cc49e7079dcd Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Wed, 13 Mar 2013 09:29:37 +0100
Subject: [PATCH 24/40] SPI: MIPS: lantiq: adds spi-xway
This patch adds support for the SPI core found on several Lantiq SoCs.
The Driver has been runtime tested in combination with m25p80 Flash Devices
on Amazon_SE and VR9.
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
---
drivers/spi/Kconfig | 8 +
drivers/spi/Makefile | 1 +
drivers/spi/spi-xway.c | 977 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 986 insertions(+)
create mode 100644 drivers/spi/spi-xway.c
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -458,6 +458,14 @@ config SPI_NUC900
help
SPI driver for Nuvoton NUC900 series ARM SoCs
+config SPI_XWAY
+ tristate "Lantiq XWAY SPI controller"
+ depends on LANTIQ && SOC_TYPE_XWAY
+ select SPI_BITBANG
+ help
+ This driver supports the Lantiq SoC SPI controller in master
+ mode.
+
#
# Add new SPI master controllers in alphabetical order above this line
#
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -69,3 +69,4 @@ obj-$(CONFIG_SPI_TOPCLIFF_PCH) += spi-t
obj-$(CONFIG_SPI_TXX9) += spi-txx9.o
obj-$(CONFIG_SPI_XCOMM) += spi-xcomm.o
obj-$(CONFIG_SPI_XILINX) += spi-xilinx.o
+obj-$(CONFIG_SPI_XWAY) += spi-xway.o
--- /dev/null
+++ b/drivers/spi/spi-xway.c
@@ -0,0 +1,977 @@
+/*
+ * Lantiq SoC SPI controller
+ *
+ * Copyright (C) 2011 Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
+ * Copyright (C) 2012 John Crispin <blogic@openwrt.org>
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/workqueue.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/spinlock.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/of_irq.h>
+
+#include <lantiq_soc.h>
+
+#define LTQ_SPI_CLC 0x00 /* Clock control */
+#define LTQ_SPI_PISEL 0x04 /* Port input select */
+#define LTQ_SPI_ID 0x08 /* Identification */
+#define LTQ_SPI_CON 0x10 /* Control */
+#define LTQ_SPI_STAT 0x14 /* Status */
+#define LTQ_SPI_WHBSTATE 0x18 /* Write HW modified state */
+#define LTQ_SPI_TB 0x20 /* Transmit buffer */
+#define LTQ_SPI_RB 0x24 /* Receive buffer */
+#define LTQ_SPI_RXFCON 0x30 /* Receive FIFO control */
+#define LTQ_SPI_TXFCON 0x34 /* Transmit FIFO control */
+#define LTQ_SPI_FSTAT 0x38 /* FIFO status */
+#define LTQ_SPI_BRT 0x40 /* Baudrate timer */
+#define LTQ_SPI_BRSTAT 0x44 /* Baudrate timer status */
+#define LTQ_SPI_SFCON 0x60 /* Serial frame control */
+#define LTQ_SPI_SFSTAT 0x64 /* Serial frame status */
+#define LTQ_SPI_GPOCON 0x70 /* General purpose output control */
+#define LTQ_SPI_GPOSTAT 0x74 /* General purpose output status */
+#define LTQ_SPI_FGPO 0x78 /* Forced general purpose output */
+#define LTQ_SPI_RXREQ 0x80 /* Receive request */
+#define LTQ_SPI_RXCNT 0x84 /* Receive count */
+#define LTQ_SPI_DMACON 0xEC /* DMA control */
+#define LTQ_SPI_IRNEN 0xF4 /* Interrupt node enable */
+#define LTQ_SPI_IRNICR 0xF8 /* Interrupt node interrupt capture */
+#define LTQ_SPI_IRNCR 0xFC /* Interrupt node control */
+
+#define LTQ_SPI_CLC_SMC_SHIFT 16 /* Clock divider for sleep mode */
+#define LTQ_SPI_CLC_SMC_MASK 0xFF
+#define LTQ_SPI_CLC_RMC_SHIFT 8 /* Clock divider for normal run mode */
+#define LTQ_SPI_CLC_RMC_MASK 0xFF
+#define LTQ_SPI_CLC_DISS BIT(1) /* Disable status bit */
+#define LTQ_SPI_CLC_DISR BIT(0) /* Disable request bit */
+
+#define LTQ_SPI_ID_TXFS_SHIFT 24 /* Implemented TX FIFO size */
+#define LTQ_SPI_ID_TXFS_MASK 0x3F
+#define LTQ_SPI_ID_RXFS_SHIFT 16 /* Implemented RX FIFO size */
+#define LTQ_SPI_ID_RXFS_MASK 0x3F
+#define LTQ_SPI_ID_REV_MASK 0x1F /* Hardware revision number */
+#define LTQ_SPI_ID_CFG BIT(5) /* DMA interface support */
+
+#define LTQ_SPI_CON_BM_SHIFT 16 /* Data width selection */
+#define LTQ_SPI_CON_BM_MASK 0x1F
+#define LTQ_SPI_CON_EM BIT(24) /* Echo mode */
+#define LTQ_SPI_CON_IDLE BIT(23) /* Idle bit value */
+#define LTQ_SPI_CON_ENBV BIT(22) /* Enable byte valid control */
+#define LTQ_SPI_CON_RUEN BIT(12) /* Receive underflow error enable */
+#define LTQ_SPI_CON_TUEN BIT(11) /* Transmit underflow error enable */
+#define LTQ_SPI_CON_AEN BIT(10) /* Abort error enable */
+#define LTQ_SPI_CON_REN BIT(9) /* Receive overflow error enable */
+#define LTQ_SPI_CON_TEN BIT(8) /* Transmit overflow error enable */
+#define LTQ_SPI_CON_LB BIT(7) /* Loopback control */
+#define LTQ_SPI_CON_PO BIT(6) /* Clock polarity control */
+#define LTQ_SPI_CON_PH BIT(5) /* Clock phase control */
+#define LTQ_SPI_CON_HB BIT(4) /* Heading control */
+#define LTQ_SPI_CON_RXOFF BIT(1) /* Switch receiver off */
+#define LTQ_SPI_CON_TXOFF BIT(0) /* Switch transmitter off */
+
+#define LTQ_SPI_STAT_RXBV_MASK 0x7
+#define LTQ_SPI_STAT_RXBV_SHIFT 28
+#define LTQ_SPI_STAT_BSY BIT(13) /* Busy flag */
+#define LTQ_SPI_STAT_RUE BIT(12) /* Receive underflow error flag */
+#define LTQ_SPI_STAT_TUE BIT(11) /* Transmit underflow error flag */
+#define LTQ_SPI_STAT_AE BIT(10) /* Abort error flag */
+#define LTQ_SPI_STAT_RE BIT(9) /* Receive error flag */
+#define LTQ_SPI_STAT_TE BIT(8) /* Transmit error flag */
+#define LTQ_SPI_STAT_MS BIT(1) /* Master/slave select bit */
+#define LTQ_SPI_STAT_EN BIT(0) /* Enable bit */
+
+#define LTQ_SPI_WHBSTATE_SETTUE BIT(15) /* Set transmit underflow error flag */
+#define LTQ_SPI_WHBSTATE_SETAE BIT(14) /* Set abort error flag */
+#define LTQ_SPI_WHBSTATE_SETRE BIT(13) /* Set receive error flag */
+#define LTQ_SPI_WHBSTATE_SETTE BIT(12) /* Set transmit error flag */
+#define LTQ_SPI_WHBSTATE_CLRTUE BIT(11) /* Clear transmit underflow error
+ flag */
+#define LTQ_SPI_WHBSTATE_CLRAE BIT(10) /* Clear abort error flag */
+#define LTQ_SPI_WHBSTATE_CLRRE BIT(9) /* Clear receive error flag */
+#define LTQ_SPI_WHBSTATE_CLRTE BIT(8) /* Clear transmit error flag */
+#define LTQ_SPI_WHBSTATE_SETME BIT(7) /* Set mode error flag */
+#define LTQ_SPI_WHBSTATE_CLRME BIT(6) /* Clear mode error flag */
+#define LTQ_SPI_WHBSTATE_SETRUE BIT(5) /* Set receive underflow error flag */
+#define LTQ_SPI_WHBSTATE_CLRRUE BIT(4) /* Clear receive underflow error flag */
+#define LTQ_SPI_WHBSTATE_SETMS BIT(3) /* Set master select bit */
+#define LTQ_SPI_WHBSTATE_CLRMS BIT(2) /* Clear master select bit */
+#define LTQ_SPI_WHBSTATE_SETEN BIT(1) /* Set enable bit (operational mode) */
+#define LTQ_SPI_WHBSTATE_CLREN BIT(0) /* Clear enable bit (config mode */
+#define LTQ_SPI_WHBSTATE_CLR_ERRORS 0x0F50
+
+#define LTQ_SPI_RXFCON_RXFITL_SHIFT 8 /* FIFO interrupt trigger level */
+#define LTQ_SPI_RXFCON_RXFITL_MASK 0x3F
+#define LTQ_SPI_RXFCON_RXFLU BIT(1) /* FIFO flush */
+#define LTQ_SPI_RXFCON_RXFEN BIT(0) /* FIFO enable */
+
+#define LTQ_SPI_TXFCON_TXFITL_SHIFT 8 /* FIFO interrupt trigger level */
+#define LTQ_SPI_TXFCON_TXFITL_MASK 0x3F
+#define LTQ_SPI_TXFCON_TXFLU BIT(1) /* FIFO flush */
+#define LTQ_SPI_TXFCON_TXFEN BIT(0) /* FIFO enable */
+
+#define LTQ_SPI_FSTAT_RXFFL_MASK 0x3f
+#define LTQ_SPI_FSTAT_RXFFL_SHIFT 0
+#define LTQ_SPI_FSTAT_TXFFL_MASK 0x3f
+#define LTQ_SPI_FSTAT_TXFFL_SHIFT 8
+
+#define LTQ_SPI_GPOCON_ISCSBN_SHIFT 8
+#define LTQ_SPI_GPOCON_INVOUTN_SHIFT 0
+
+#define LTQ_SPI_FGPO_SETOUTN_SHIFT 8
+#define LTQ_SPI_FGPO_CLROUTN_SHIFT 0
+
+#define LTQ_SPI_RXREQ_RXCNT_MASK 0xFFFF /* Receive count value */
+#define LTQ_SPI_RXCNT_TODO_MASK 0xFFFF /* Recevie to-do value */
+
+#define LTQ_SPI_IRNEN_F BIT(3) /* Frame end interrupt request */
+#define LTQ_SPI_IRNEN_E BIT(2) /* Error end interrupt request */
+#define LTQ_SPI_IRNEN_T BIT(1) /* Transmit end interrupt request */
+#define LTQ_SPI_IRNEN_R BIT(0) /* Receive end interrupt request */
+#define LTQ_SPI_IRNEN_ALL 0xF
+
+struct ltq_spi {
+ struct spi_bitbang bitbang;
+ struct completion done;
+ spinlock_t lock;
+
+ struct device *dev;
+ void __iomem *base;
+ struct clk *fpiclk;
+ struct clk *spiclk;
+
+ int status;
+ int irq[3];
+
+ const u8 *tx;
+ u8 *rx;
+ u32 tx_cnt;
+ u32 rx_cnt;
+ u32 len;
+ struct spi_transfer *curr_transfer;
+
+ u32 (*get_tx) (struct ltq_spi *);
+
+ u16 txfs;
+ u16 rxfs;
+ unsigned dma_support:1;
+ unsigned cfg_mode:1;
+};
+
+static inline struct ltq_spi *ltq_spi_to_hw(struct spi_device *spi)
+{
+ return spi_master_get_devdata(spi->master);
+}
+
+static inline u32 ltq_spi_reg_read(struct ltq_spi *hw, u32 reg)
+{
+ return ioread32be(hw->base + reg);
+}
+
+static inline void ltq_spi_reg_write(struct ltq_spi *hw, u32 val, u32 reg)
+{
+ iowrite32be(val, hw->base + reg);
+}
+
+static inline void ltq_spi_reg_setbit(struct ltq_spi *hw, u32 bits, u32 reg)
+{
+ u32 val;
+
+ val = ltq_spi_reg_read(hw, reg);
+ val |= bits;
+ ltq_spi_reg_write(hw, val, reg);
+}
+
+static inline void ltq_spi_reg_clearbit(struct ltq_spi *hw, u32 bits, u32 reg)
+{
+ u32 val;
+
+ val = ltq_spi_reg_read(hw, reg);
+ val &= ~bits;
+ ltq_spi_reg_write(hw, val, reg);
+}
+
+static void ltq_spi_hw_enable(struct ltq_spi *hw)
+{
+ u32 clc;
+
+ /* Power-up module */
+ clk_enable(hw->spiclk);
+
+ /*
+ * Set clock divider for run mode to 1 to
+ * run at same frequency as FPI bus
+ */
+ clc = (1 << LTQ_SPI_CLC_RMC_SHIFT);
+ ltq_spi_reg_write(hw, clc, LTQ_SPI_CLC);
+}
+
+static void ltq_spi_hw_disable(struct ltq_spi *hw)
+{
+ /* Set clock divider to 0 and set module disable bit */
+ ltq_spi_reg_write(hw, LTQ_SPI_CLC_DISS, LTQ_SPI_CLC);
+
+ /* Power-down module */
+ clk_disable(hw->spiclk);
+}
+
+static void ltq_spi_reset_fifos(struct ltq_spi *hw)
+{
+ u32 val;
+
+ /*
+ * Enable and flush FIFOs. Set interrupt trigger level to
+ * half of FIFO count implemented in hardware.
+ */
+ if (hw->txfs > 1) {
+ val = hw->txfs << (LTQ_SPI_TXFCON_TXFITL_SHIFT - 1);
+ val |= LTQ_SPI_TXFCON_TXFEN | LTQ_SPI_TXFCON_TXFLU;
+ ltq_spi_reg_write(hw, val, LTQ_SPI_TXFCON);
+ }
+
+ if (hw->rxfs > 1) {
+ val = hw->rxfs << (LTQ_SPI_RXFCON_RXFITL_SHIFT - 1);
+ val |= LTQ_SPI_RXFCON_RXFEN | LTQ_SPI_RXFCON_RXFLU;
+ ltq_spi_reg_write(hw, val, LTQ_SPI_RXFCON);
+ }
+}
+
+static inline int ltq_spi_wait_ready(struct ltq_spi *hw)
+{
+ u32 stat;
+ unsigned long timeout;
+
+ timeout = jiffies + msecs_to_jiffies(200);
+
+ do {
+ stat = ltq_spi_reg_read(hw, LTQ_SPI_STAT);
+ if (!(stat & LTQ_SPI_STAT_BSY))
+ return 0;
+
+ cond_resched();
+ } while (!time_after_eq(jiffies, timeout));
+
+ dev_err(hw->dev, "SPI wait ready timed out stat: %x\n", stat);
+
+ return -ETIMEDOUT;
+}
+
+static void ltq_spi_config_mode_set(struct ltq_spi *hw)
+{
+ if (hw->cfg_mode)
+ return;
+
+ /*
+ * Putting the SPI module in config mode is only safe if no
+ * transfer is in progress as indicated by busy flag STATE.BSY.
+ */
+ if (ltq_spi_wait_ready(hw)) {
+ ltq_spi_reset_fifos(hw);
+ hw->status = -ETIMEDOUT;
+ }
+ ltq_spi_reg_write(hw, LTQ_SPI_WHBSTATE_CLREN, LTQ_SPI_WHBSTATE);
+
+ hw->cfg_mode = 1;
+}
+
+static void ltq_spi_run_mode_set(struct ltq_spi *hw)
+{
+ if (!hw->cfg_mode)
+ return;
+
+ ltq_spi_reg_write(hw, LTQ_SPI_WHBSTATE_SETEN, LTQ_SPI_WHBSTATE);
+
+ hw->cfg_mode = 0;
+}
+
+static u32 ltq_spi_tx_word_u8(struct ltq_spi *hw)
+{
+ const u8 *tx = hw->tx;
+ u32 data = *tx++;
+
+ hw->tx_cnt++;
+ hw->tx++;
+
+ return data;
+}
+
+static u32 ltq_spi_tx_word_u16(struct ltq_spi *hw)
+{
+ const u16 *tx = (u16 *) hw->tx;
+ u32 data = *tx++;
+
+ hw->tx_cnt += 2;
+ hw->tx += 2;
+
+ return data;
+}
+
+static u32 ltq_spi_tx_word_u32(struct ltq_spi *hw)
+{
+ const u32 *tx = (u32 *) hw->tx;
+ u32 data = *tx++;
+
+ hw->tx_cnt += 4;
+ hw->tx += 4;
+
+ return data;
+}
+
+static void ltq_spi_bits_per_word_set(struct spi_device *spi)
+{
+ struct ltq_spi *hw = ltq_spi_to_hw(spi);
+ u32 bm;
+ u8 bits_per_word = spi->bits_per_word;
+
+ /*
+ * Use either default value of SPI device or value
+ * from current transfer.
+ */
+ if (hw->curr_transfer && hw->curr_transfer->bits_per_word)
+ bits_per_word = hw->curr_transfer->bits_per_word;
+
+ if (bits_per_word <= 8)
+ hw->get_tx = ltq_spi_tx_word_u8;
+ else if (bits_per_word <= 16)
+ hw->get_tx = ltq_spi_tx_word_u16;
+ else if (bits_per_word <= 32)
+ hw->get_tx = ltq_spi_tx_word_u32;
+
+ /* CON.BM value = bits_per_word - 1 */
+ bm = (bits_per_word - 1) << LTQ_SPI_CON_BM_SHIFT;
+
+ ltq_spi_reg_clearbit(hw, LTQ_SPI_CON_BM_MASK <<
+ LTQ_SPI_CON_BM_SHIFT, LTQ_SPI_CON);
+ ltq_spi_reg_setbit(hw, bm, LTQ_SPI_CON);
+}
+
+static void ltq_spi_speed_set(struct spi_device *spi)
+{
+ struct ltq_spi *hw = ltq_spi_to_hw(spi);
+ u32 br, max_speed_hz, spi_clk;
+ u32 speed_hz = spi->max_speed_hz;
+
+ /*
+ * Use either default value of SPI device or value
+ * from current transfer.
+ */
+ if (hw->curr_transfer && hw->curr_transfer->speed_hz)
+ speed_hz = hw->curr_transfer->speed_hz;
+
+ /*
+ * SPI module clock is derived from FPI bus clock dependent on
+ * divider value in CLC.RMS which is always set to 1.
+ */
+ spi_clk = clk_get_rate(hw->fpiclk);
+
+ /*
+ * Maximum SPI clock frequency in master mode is half of
+ * SPI module clock frequency. Maximum reload value of
+ * baudrate generator BR is 2^16.
+ */
+ max_speed_hz = spi_clk / 2;
+ if (speed_hz >= max_speed_hz)
+ br = 0;
+ else
+ br = (max_speed_hz / speed_hz) - 1;
+
+ if (br > 0xFFFF)
+ br = 0xFFFF;
+
+ ltq_spi_reg_write(hw, br, LTQ_SPI_BRT);
+}
+
+static void ltq_spi_clockmode_set(struct spi_device *spi)
+{
+ struct ltq_spi *hw = ltq_spi_to_hw(spi);
+ u32 con;
+
+ con = ltq_spi_reg_read(hw, LTQ_SPI_CON);
+
+ /*
+ * SPI mode mapping in CON register:
+ * Mode CPOL CPHA CON.PO CON.PH
+ * 0 0 0 0 1
+ * 1 0 1 0 0
+ * 2 1 0 1 1
+ * 3 1 1 1 0
+ */
+ if (spi->mode & SPI_CPHA)
+ con &= ~LTQ_SPI_CON_PH;
+ else
+ con |= LTQ_SPI_CON_PH;
+
+ if (spi->mode & SPI_CPOL)
+ con |= LTQ_SPI_CON_PO;
+ else
+ con &= ~LTQ_SPI_CON_PO;
+
+ /* Set heading control */
+ if (spi->mode & SPI_LSB_FIRST)
+ con &= ~LTQ_SPI_CON_HB;
+ else
+ con |= LTQ_SPI_CON_HB;
+
+ ltq_spi_reg_write(hw, con, LTQ_SPI_CON);
+}
+
+static void ltq_spi_xmit_set(struct ltq_spi *hw, struct spi_transfer *t)
+{
+ u32 con;
+
+ con = ltq_spi_reg_read(hw, LTQ_SPI_CON);
+
+ if (t) {
+ if (t->tx_buf && t->rx_buf) {
+ con &= ~(LTQ_SPI_CON_TXOFF | LTQ_SPI_CON_RXOFF);
+ } else if (t->rx_buf) {
+ con &= ~LTQ_SPI_CON_RXOFF;
+ con |= LTQ_SPI_CON_TXOFF;
+ } else if (t->tx_buf) {
+ con &= ~LTQ_SPI_CON_TXOFF;
+ con |= LTQ_SPI_CON_RXOFF;
+ }
+ } else
+ con |= (LTQ_SPI_CON_TXOFF | LTQ_SPI_CON_RXOFF);
+
+ ltq_spi_reg_write(hw, con, LTQ_SPI_CON);
+}
+
+static void ltq_spi_internal_cs_activate(struct spi_device *spi)
+{
+ struct ltq_spi *hw = ltq_spi_to_hw(spi);
+ u32 fgpo;
+
+ fgpo = (1 << (spi->chip_select + LTQ_SPI_FGPO_CLROUTN_SHIFT));
+ ltq_spi_reg_setbit(hw, fgpo, LTQ_SPI_FGPO);
+}
+
+static void ltq_spi_internal_cs_deactivate(struct spi_device *spi)
+{
+ struct ltq_spi *hw = ltq_spi_to_hw(spi);
+ u32 fgpo;
+
+ fgpo = (1 << (spi->chip_select + LTQ_SPI_FGPO_SETOUTN_SHIFT));
+ ltq_spi_reg_setbit(hw, fgpo, LTQ_SPI_FGPO);
+}
+
+static void ltq_spi_chipselect(struct spi_device *spi, int cs)
+{
+ struct ltq_spi *hw = ltq_spi_to_hw(spi);
+
+ switch (cs) {
+ case BITBANG_CS_ACTIVE:
+ ltq_spi_bits_per_word_set(spi);
+ ltq_spi_speed_set(spi);
+ ltq_spi_clockmode_set(spi);
+ ltq_spi_run_mode_set(hw);
+ ltq_spi_internal_cs_activate(spi);
+ break;
+
+ case BITBANG_CS_INACTIVE:
+ ltq_spi_internal_cs_deactivate(spi);
+ ltq_spi_config_mode_set(hw);
+ break;
+ }
+}
+
+static int ltq_spi_setup_transfer(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct ltq_spi *hw = ltq_spi_to_hw(spi);
+ u8 bits_per_word = spi->bits_per_word;
+
+ hw->curr_transfer = t;
+
+ if (t && t->bits_per_word)
+ bits_per_word = t->bits_per_word;
+
+ if (bits_per_word > 32)
+ return -EINVAL;
+
+ ltq_spi_config_mode_set(hw);
+
+ return 0;
+}
+
+static int ltq_spi_setup(struct spi_device *spi)
+{
+ struct ltq_spi *hw = ltq_spi_to_hw(spi);
+ u32 gpocon, fgpo;
+
+ /* Set default word length to 8 if not set */
+ if (!spi->bits_per_word)
+ spi->bits_per_word = 8;
+
+ if (spi->bits_per_word > 32)
+ return -EINVAL;
+
+ /*
+ * Up to six GPIOs can be connected to the SPI module
+ * via GPIO alternate function to control the chip select lines.
+ */
+ gpocon = (1 << (spi->chip_select +
+ LTQ_SPI_GPOCON_ISCSBN_SHIFT));
+
+ if (spi->mode & SPI_CS_HIGH)
+ gpocon |= (1 << spi->chip_select);
+
+ fgpo = (1 << (spi->chip_select + LTQ_SPI_FGPO_SETOUTN_SHIFT));
+
+ ltq_spi_reg_setbit(hw, gpocon, LTQ_SPI_GPOCON);
+ ltq_spi_reg_setbit(hw, fgpo, LTQ_SPI_FGPO);
+
+ return 0;
+}
+
+static void ltq_spi_cleanup(struct spi_device *spi)
+{
+
+}
+
+static void ltq_spi_txfifo_write(struct ltq_spi *hw)
+{
+ u32 fstat, data;
+ u16 fifo_space;
+
+ /* Determine how much FIFOs are free for TX data */
+ fstat = ltq_spi_reg_read(hw, LTQ_SPI_FSTAT);
+ fifo_space = hw->txfs - ((fstat >> LTQ_SPI_FSTAT_TXFFL_SHIFT) &
+ LTQ_SPI_FSTAT_TXFFL_MASK);
+
+ if (!fifo_space)
+ return;
+
+ while (hw->tx_cnt < hw->len && fifo_space) {
+ data = hw->get_tx(hw);
+ ltq_spi_reg_write(hw, data, LTQ_SPI_TB);
+ fifo_space--;
+ }
+}
+
+static void ltq_spi_rxfifo_read(struct ltq_spi *hw)
+{
+ u32 fstat, data, *rx32;
+ u16 fifo_fill;
+ u8 rxbv, shift, *rx8;
+
+ /* Determine how much FIFOs are filled with RX data */
+ fstat = ltq_spi_reg_read(hw, LTQ_SPI_FSTAT);
+ fifo_fill = ((fstat >> LTQ_SPI_FSTAT_RXFFL_SHIFT)
+ & LTQ_SPI_FSTAT_RXFFL_MASK);
+
+ if (!fifo_fill)
+ return;
+
+ /*
+ * The 32 bit FIFO is always used completely independent from the
+ * bits_per_word value. Thus four bytes have to be read at once
+ * per FIFO.
+ */
+ rx32 = (u32 *) hw->rx;
+ while (hw->len - hw->rx_cnt >= 4 && fifo_fill) {
+ *rx32++ = ltq_spi_reg_read(hw, LTQ_SPI_RB);
+ hw->rx_cnt += 4;
+ hw->rx += 4;
+ fifo_fill--;
+ }
+
+ /*
+ * If there are remaining bytes, read byte count from STAT.RXBV
+ * register and read the data byte-wise.
+ */
+ while (fifo_fill && hw->rx_cnt < hw->len) {
+ rxbv = (ltq_spi_reg_read(hw, LTQ_SPI_STAT) >>
+ LTQ_SPI_STAT_RXBV_SHIFT) & LTQ_SPI_STAT_RXBV_MASK;
+ data = ltq_spi_reg_read(hw, LTQ_SPI_RB);
+
+ shift = (rxbv - 1) * 8;
+ rx8 = hw->rx;
+
+ while (rxbv) {
+ *rx8++ = (data >> shift) & 0xFF;
+ rxbv--;
+ shift -= 8;
+ hw->rx_cnt++;
+ hw->rx++;
+ }
+
+ fifo_fill--;
+ }
+}
+
+static void ltq_spi_rxreq_set(struct ltq_spi *hw)
+{
+ u32 rxreq, rxreq_max, rxtodo;
+
+ rxtodo = ltq_spi_reg_read(hw, LTQ_SPI_RXCNT) & LTQ_SPI_RXCNT_TODO_MASK;
+
+ /*
+ * In RX-only mode the serial clock is activated only after writing
+ * the expected amount of RX bytes into RXREQ register.
+ * To avoid receive overflows at high clocks it is better to request
+ * only the amount of bytes that fits into all FIFOs. This value
+ * depends on the FIFO size implemented in hardware.
+ */
+ rxreq = hw->len - hw->rx_cnt;
+ rxreq_max = hw->rxfs << 2;
+ rxreq = min(rxreq_max, rxreq);
+
+ if (!rxtodo && rxreq)
+ ltq_spi_reg_write(hw, rxreq, LTQ_SPI_RXREQ);
+}
+
+static inline void ltq_spi_complete(struct ltq_spi *hw)
+{
+ complete(&hw->done);
+}
+
+irqreturn_t ltq_spi_tx_irq(int irq, void *data)
+{
+ struct ltq_spi *hw = data;
+ unsigned long flags;
+ int completed = 0;
+
+ spin_lock_irqsave(&hw->lock, flags);
+
+ if (hw->tx_cnt < hw->len)
+ ltq_spi_txfifo_write(hw);
+
+ if (hw->tx_cnt == hw->len)
+ completed = 1;
+
+ spin_unlock_irqrestore(&hw->lock, flags);
+
+ if (completed)
+ ltq_spi_complete(hw);
+
+ return IRQ_HANDLED;
+}
+
+irqreturn_t ltq_spi_rx_irq(int irq, void *data)
+{
+ struct ltq_spi *hw = data;
+ unsigned long flags;
+ int completed = 0;
+
+ spin_lock_irqsave(&hw->lock, flags);
+
+ if (hw->rx_cnt < hw->len) {
+ ltq_spi_rxfifo_read(hw);
+
+ if (hw->tx && hw->tx_cnt < hw->len)
+ ltq_spi_txfifo_write(hw);
+ }
+
+ if (hw->rx_cnt == hw->len)
+ completed = 1;
+ else if (!hw->tx)
+ ltq_spi_rxreq_set(hw);
+
+ spin_unlock_irqrestore(&hw->lock, flags);
+
+ if (completed)
+ ltq_spi_complete(hw);
+
+ return IRQ_HANDLED;
+}
+
+irqreturn_t ltq_spi_err_irq(int irq, void *data)
+{
+ struct ltq_spi *hw = data;
+ unsigned long flags;
+
+ spin_lock_irqsave(&hw->lock, flags);
+
+ /* Disable all interrupts */
+ ltq_spi_reg_clearbit(hw, LTQ_SPI_IRNEN_ALL, LTQ_SPI_IRNEN);
+
+ /* Clear all error flags */
+ ltq_spi_reg_write(hw, LTQ_SPI_WHBSTATE_CLR_ERRORS, LTQ_SPI_WHBSTATE);
+
+ /* Flush FIFOs */
+ ltq_spi_reg_setbit(hw, LTQ_SPI_RXFCON_RXFLU, LTQ_SPI_RXFCON);
+ ltq_spi_reg_setbit(hw, LTQ_SPI_TXFCON_TXFLU, LTQ_SPI_TXFCON);
+
+ hw->status = -EIO;
+ spin_unlock_irqrestore(&hw->lock, flags);
+
+ ltq_spi_complete(hw);
+
+ return IRQ_HANDLED;
+}
+
+static int ltq_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct ltq_spi *hw = ltq_spi_to_hw(spi);
+ u32 irq_flags = 0;
+
+ hw->tx = t->tx_buf;
+ hw->rx = t->rx_buf;
+ hw->len = t->len;
+ hw->tx_cnt = 0;
+ hw->rx_cnt = 0;
+ hw->status = 0;
+ INIT_COMPLETION(hw->done);
+
+ ltq_spi_xmit_set(hw, t);
+
+ /* Enable error interrupts */
+ ltq_spi_reg_setbit(hw, LTQ_SPI_IRNEN_E, LTQ_SPI_IRNEN);
+
+ if (hw->tx) {
+ /* Initially fill TX FIFO with as much data as possible */
+ ltq_spi_txfifo_write(hw);
+ irq_flags |= LTQ_SPI_IRNEN_T;
+
+ /* Always enable RX interrupt in Full Duplex mode */
+ if (hw->rx)
+ irq_flags |= LTQ_SPI_IRNEN_R;
+ } else if (hw->rx) {
+ /* Start RX clock */
+ ltq_spi_rxreq_set(hw);
+
+ /* Enable RX interrupt to receive data from RX FIFOs */
+ irq_flags |= LTQ_SPI_IRNEN_R;
+ }
+
+ /* Enable TX or RX interrupts */
+ ltq_spi_reg_setbit(hw, irq_flags, LTQ_SPI_IRNEN);
+ wait_for_completion_interruptible(&hw->done);
+
+ /* Disable all interrupts */
+ ltq_spi_reg_clearbit(hw, LTQ_SPI_IRNEN_ALL, LTQ_SPI_IRNEN);
+
+ /*
+ * Return length of current transfer for bitbang utility code if
+ * no errors occured during transmission.
+ */
+ if (!hw->status)
+ hw->status = hw->len;
+
+ return hw->status;
+}
+
+static const struct ltq_spi_irq_map {
+ char *name;
+ irq_handler_t handler;
+} ltq_spi_irqs[] = {
+ { "spi_rx", ltq_spi_rx_irq },
+ { "spi_tx", ltq_spi_tx_irq },
+ { "spi_err", ltq_spi_err_irq },
+};
+
+static int ltq_spi_probe(struct platform_device *pdev)
+{
+ struct resource irqres[3];
+ struct spi_master *master;
+ struct resource *r;
+ struct ltq_spi *hw;
+ int ret, i;
+ u32 data, id;
+
+ if (of_irq_to_resource_table(pdev->dev.of_node, irqres, 3) != 3) {
+ dev_err(&pdev->dev, "IRQ settings missing in device tree\n");
+ return -EINVAL;
+ }
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct ltq_spi));
+ if (!master) {
+ dev_err(&pdev->dev, "spi_alloc_master\n");
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ hw = spi_master_get_devdata(master);
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (r == NULL) {
+ dev_err(&pdev->dev, "platform_get_resource\n");
+ ret = -ENOENT;
+ goto err_master;
+ }
+
+ r = devm_request_mem_region(&pdev->dev, r->start, resource_size(r),
+ pdev->name);
+ if (!r) {
+ dev_err(&pdev->dev, "failed to request memory region\n");
+ ret = -ENXIO;
+ goto err_master;
+ }
+
+ hw->base = devm_ioremap_nocache(&pdev->dev, r->start, resource_size(r));
+ if (!hw->base) {
+ dev_err(&pdev->dev, "failed to remap memory region\n");
+ ret = -ENXIO;
+ goto err_master;
+ }
+
+ memset(hw->irq, 0, sizeof(hw->irq));
+ for (i = 0; i < ARRAY_SIZE(ltq_spi_irqs); i++) {
+ hw->irq[i] = irqres[i].start;
+ ret = request_irq(hw->irq[i], ltq_spi_irqs[i].handler,
+ 0, ltq_spi_irqs[i].name, hw);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request %s irq (%d)\n",
+ ltq_spi_irqs[i].name, hw->irq[i]);
+ goto err_irq;
+ }
+ }
+
+ hw->fpiclk = clk_get_fpi();
+ if (IS_ERR(hw->fpiclk)) {
+ dev_err(&pdev->dev, "failed to get fpi clock\n");
+ ret = PTR_ERR(hw->fpiclk);
+ goto err_clk;
+ }
+
+ hw->spiclk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(hw->spiclk)) {
+ dev_err(&pdev->dev, "failed to get spi clock gate\n");
+ ret = PTR_ERR(hw->spiclk);
+ goto err_clk;
+ }
+
+ hw->bitbang.master = spi_master_get(master);
+ hw->bitbang.chipselect = ltq_spi_chipselect;
+ hw->bitbang.setup_transfer = ltq_spi_setup_transfer;
+ hw->bitbang.txrx_bufs = ltq_spi_txrx_bufs;
+
+ if (of_machine_is_compatible("lantiq,ase"))
+ master->num_chipselect = 3;
+ else
+ master->num_chipselect = 6;
+ master->bus_num = pdev->id;
+ master->setup = ltq_spi_setup;
+ master->cleanup = ltq_spi_cleanup;
+ master->dev.of_node = pdev->dev.of_node;
+
+ hw->dev = &pdev->dev;
+ init_completion(&hw->done);
+ spin_lock_init(&hw->lock);
+
+ ltq_spi_hw_enable(hw);
+
+ /* Read module capabilities */
+ id = ltq_spi_reg_read(hw, LTQ_SPI_ID);
+ hw->txfs = (id >> LTQ_SPI_ID_TXFS_SHIFT) & LTQ_SPI_ID_TXFS_MASK;
+ hw->rxfs = (id >> LTQ_SPI_ID_TXFS_SHIFT) & LTQ_SPI_ID_TXFS_MASK;
+ hw->dma_support = (id & LTQ_SPI_ID_CFG) ? 1 : 0;
+
+ ltq_spi_config_mode_set(hw);
+
+ /* Enable error checking, disable TX/RX, set idle value high */
+ data = LTQ_SPI_CON_RUEN | LTQ_SPI_CON_AEN |
+ LTQ_SPI_CON_TEN | LTQ_SPI_CON_REN |
+ LTQ_SPI_CON_TXOFF | LTQ_SPI_CON_RXOFF | LTQ_SPI_CON_IDLE;
+ ltq_spi_reg_write(hw, data, LTQ_SPI_CON);
+
+ /* Enable master mode and clear error flags */
+ ltq_spi_reg_write(hw, LTQ_SPI_WHBSTATE_SETMS |
+ LTQ_SPI_WHBSTATE_CLR_ERRORS, LTQ_SPI_WHBSTATE);
+
+ /* Reset GPIO/CS registers */
+ ltq_spi_reg_write(hw, 0x0, LTQ_SPI_GPOCON);
+ ltq_spi_reg_write(hw, 0xFF00, LTQ_SPI_FGPO);
+
+ /* Enable and flush FIFOs */
+ ltq_spi_reset_fifos(hw);
+
+ ret = spi_bitbang_start(&hw->bitbang);
+ if (ret) {
+ dev_err(&pdev->dev, "spi_bitbang_start failed\n");
+ goto err_bitbang;
+ }
+
+ platform_set_drvdata(pdev, hw);
+
+ pr_info("Lantiq SoC SPI controller rev %u (TXFS %u, RXFS %u, DMA %u)\n",
+ id & LTQ_SPI_ID_REV_MASK, hw->txfs, hw->rxfs, hw->dma_support);
+
+ return 0;
+
+err_bitbang:
+ ltq_spi_hw_disable(hw);
+
+err_clk:
+ if (hw->fpiclk)
+ clk_put(hw->fpiclk);
+ if (hw->spiclk)
+ clk_put(hw->spiclk);
+
+err_irq:
+ clk_put(hw->fpiclk);
+
+ for (; i > 0; i--)
+ free_irq(hw->irq[i], hw);
+
+err_master:
+ spi_master_put(master);
+
+err:
+ return ret;
+}
+
+static int ltq_spi_remove(struct platform_device *pdev)
+{
+ struct ltq_spi *hw = platform_get_drvdata(pdev);
+ int ret, i;
+
+ ret = spi_bitbang_stop(&hw->bitbang);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, NULL);
+
+ ltq_spi_config_mode_set(hw);
+ ltq_spi_hw_disable(hw);
+
+ for (i = 0; i < ARRAY_SIZE(hw->irq); i++)
+ if (0 < hw->irq[i])
+ free_irq(hw->irq[i], hw);
+
+ if (hw->fpiclk)
+ clk_put(hw->fpiclk);
+ if (hw->spiclk)
+ clk_put(hw->spiclk);
+
+ spi_master_put(hw->bitbang.master);
+
+ return 0;
+}
+
+static const struct of_device_id ltq_spi_match[] = {
+ { .compatible = "lantiq,spi-xway" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ltq_spi_match);
+
+static struct platform_driver ltq_spi_driver = {
+ .probe = ltq_spi_probe,
+ .remove = ltq_spi_remove,
+ .driver = {
+ .name = "spi-xway",
+ .owner = THIS_MODULE,
+ .of_match_table = ltq_spi_match,
+ },
+};
+
+module_platform_driver(ltq_spi_driver);
+
+MODULE_DESCRIPTION("Lantiq SoC SPI controller driver");
+MODULE_AUTHOR("Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:spi-xway");
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